This invention relates in general to noise and vibration dampening structures for use with rotating articles, such as a driveshaft assembly in a vehicular drive train system. In particular, this invention relates to an improved structure and method of manufacturing such a noise and vibration damper for use on a component of a vehicular driveshaft assembly.
Drive train systems are widely used for generating power from a source and for transferring such power from the source to a driven mechanism. Frequently, the source generates rotational power, and such rotational power is transferred from the source to a rotatably driven mechanism. For example, in most land vehicles in use today, an engine/transmission assembly generates rotational power, and such rotational power is transferred from an output shaft of the engine/transmission assembly through a driveshaft assembly to an input shaft of an axle assembly so as to rotatably drive the wheels of the vehicle. To accomplish this, a typical driveshaft assembly includes a hollow cylindrical driveshaft tube having a pair of end fittings, such as a pair of tube yokes, secured to the front and rear ends thereof. The front end fitting forms a portion of a front universal joint that connects the output shaft of the engine/transmission assembly to the front end of the driveshaft tube. Similarly, the rear end fitting forms a portion of a rear universal joint that connects the rear end of the driveshaft tube to the input shaft of the axle assembly. The front and rear universal joints provide a rotational driving connection from the output shaft of the engine/transmission assembly through the driveshaft tube to the input shaft of the axle assembly, while accommodating a limited amount of angular misalignment between the rotational axes of these three shafts.
One problem that is often encountered in vehicular driveshaft assemblies and other rotatable structures is that they tend to transmit and amplify undesirable noise and vibration that are encountered during operation. For example, in the context of the above-described vehicular drive train system, it is known that the meshing of the gears contained within the engine/transmission assembly and within the axle assembly can generate undesirable noise and vibration. Such noise and vibration can be transmitted and amplified by the relatively lengthy driveshaft assembly that is connected to the output shaft of the engine/transmission assembly and to the input shaft of the axle assembly, as described above. In order to provide the passengers with a more quiet and comfortable ride, it has been found to be desirable to minimize the transmission and amplification of such noise and vibration by the vehicular driveshaft assembly.
To accomplish this, it is known to provide a noise and vibration damper on one or more components of the vehicular driveshaft assembly. A typical noise and vibration damper includes an inner annular member that is press fit onto an outer surface of the component of the driveshaft assembly, an outer annular member that is disposed about the inner annular member, and a layer of an elastomeric material that extends between the inner and outer annular members. In the past, the inner annular member has been formed from a ring of steel that was machined to a desired shape, while the outer annular member has been formed from a ring of steel or cast iron that that was also machined to a desired shape. Although effective, this structure has been found to be relatively heavy and expensive to manufacture. Thus, it would be desirable to provide an improved structure and method of manufacturing a noise and vibration damper for use with a rotatable structure, such as a driveshaft assembly for a vehicular drive train system, that is lighter and less expensive to manufacture than known dampers.